'Are you thinking what we're thinking?' the Tory poster asks. Which is, it turns out: 'It's not racist to impose limits on immigration.' A mixed-race friend of mine who is completely apolitical got the point at once. 'It's a bit BNP,' she told me, frowning.

In other days, this insinuating nastiness would be sufficient in itself to begin to get the theatre, wine and book-club set heading back for the Labour camp. If nothing else, it's a reminder of some of the darker impulses that connect the electorate with the right wing of politics. Not now. Every anecdote I hear from every dining-room and foyer in well-heeled liberal Britain is of how no one is voting for Blair. They prefer the Lib Dems, they'll give the Greens a go, they won't turn up at all. As the trendy T-shirt people have it, the PM is Tony Blair.

It's a tender moment, then, for director Peter Kosminsky's latest docudrama, this one on the death of Dr David Kelly, to appear on Channel 4. Will it indict Blair still further? Strengthen the impression of the PM's essential snakishness, of his being a pretty slippery kind of a guy? Certainly, the strongest speech is Kelly's mid-crisis complaint to his wife that he is being sacrificed by the government as a form of diversion from the failure to find WMD in Iraq.

The only problem with this is that, by the time you get to this scene, you already know that Kelly is wrong. This is not a diversion; it's a desperate and unlovely attempt to save the reputation of the government from the charge that they concocted evidence to make the case for war, against the wishes of the intelligence community.

In May 2003, Andrew Gilligan famously asserted that 'a week before publication' (of the September dossier), Downing Street 'ordered it to be sexed up ... and ordered more facts to be discovered'. The following weekend in the Mail on Sunday, Gilligan elaborated: 'I asked my intelligence source why Blair misled us all over Saddam's WMD. His response? One word ... Campbell.' For weeks, various parts of the BBC continued to make the claim that the complaint of government ill-doing came from the heart of spookery. News 24 on 4 June 2003, for example, began an item: 'An unnamed intelligence officer has told a BBC journalist that the government probably exaggerated the threat posed by Saddam in order to justify the war.'

This source was David Kelly and the recollection was Gilligan's. But around the same time, Kelly had had a conversation with Newsnight reporter Susan Watts. This conversation was taped. Kelly told Watts: 'You have to remember I'm not part of the intelligence community.' Watts asked him about WMD. 'My own perception is, yes, they have weapons,' said Kelly. 'A "clear and imminent threat?"' 'Yes.'

If Kelly had said the same things to Gilligan as he had to Watts, then the conclusion was that the Today man had, in the words of Professor Anthony Glees, 'exaggerated and displaced the whole meaning of Kelly's gripe'. And this is strongly suggested by the Kosminsky drama. In it, we are shown Gilligan adding material to his supposedly contemporary notes of the Kelly meeting weeks later. The producers, with the help of Professor Barrett, have concluded that Gilligan altered his notes and then reset the computer's internal clock to cover up what he had done.

Gilligan himself denies this, calling it 'demonstrably, even absurdly false'. If that's right, then a libel action is inevitable. If no such proceedings are undertaken, then we are going to have to conclude that Kosminsky is on to something.

Politically, IT may not matter. Last week, our own Tim Adams interviewed Mark Rylance, who plays, brilliantly, Kelly. Rylance seems unaware of the implication of the Gilligan scene and the Watts tape. Before Kelly's possibly fatal appearance at the Foreign Affairs committee, Rylance muses that Kelly 'must have known there was another possibility. One in which he went into the committee and told the full truth. "Yes, I did say something like that to Andrew Gilligan, and believe I was right to do so after what I witnessed" and so on.'

In other words, Rylance has decided that it is the government that's guilty, despite what is suggested in his own drama. Adams then asked the actor whether he was comfortable with the PM being depicted as saying things in private meetings that he expressly denied having said? 'I'm afraid,' Rylance said, 'that I feel there is enough general evidence in this Prime Minister's term that these kinds of questions must be asked, and that this is one powerful and justifiable way of asking them.'

The Rylance version is what many people believe. They believe, as Glees suggests that the BBC inferred, that 'the intelligence supplied by the JIC [Joint Intelligence Committee] did not support the government's case for war, so that the government then embellished or invented intelligence'. Or, as Adam Price, the Plaid Cymru MP leading the Impeach Blair movement, has put it, the PM is guilty of 'deliberate repeated distortion, seriously misleading statements and culpable negligence'. In particular, Blair 'exaggerated the condition of Iraq's illicit weapons well beyond the assessments of the intelligence services or the UN inspectors'.

So this is what I want to say. This accusation is wrong and scrutiny of the Hutton and Butler reports (not so much their findings) and the evidence submitted to the inquiries shows that Blair was setting out - albeit in leadership-speak - what he was being told by the intelligence services. I recommend to readers Tim Coates's paperback precis of Butler. There you find the JIC's increasingly terrifying assessments on terrorism and WMD and the main JIC assessments of Iraq. These, says Butler, were psychologically affected by the maturity and extent of Iraqi WMD programmes discovered after 1991 and the determination of the regime to hide them.

By May 2001, the record shows the JIC reporting that 'intelligence gives grounds for concern and suggests that Iraq is becoming bolder in conducting activities prohibited by UN resolution 687'. Further: 'We judge, but cannot confirm, that Iraq is conducting nuclear related research ... and could have longer term plans to produce enriched uranium for weapons.' Plus: 'Good intelligence of Iraq's former chemical and biological warfare facilities ... taken together ... suggests a continuing research and development programme.'

In April 2000: 'There is clear evidence of continuing Iraqi biological warfare activity, including BW- related research and the production of BW agent.' The JIC assessed that 'Iraq has retained sufficient expertise to produce BW agents within weeks using legitimate biotechnology facilities', that there were attempts to recruit new scientists for BW work, and that 'Iraq has increased the pace and scope of its missile research and development programmes'.

By March 2002, the JIC was advising the government that the Iraqis could produce sarin gas and VX 'and in the case of VX may already have done so'. As Butler summed it up: 'Intelligence supporting the JIC's judgments on Iraqi research and development programmes came from a range of sources and was, in our view, substantial.' Butler went on, more tellingly: 'By mid-September 2002, therefore, readers of JIC assessments' (ie Blair) would have had the following impressions: 'Continuing clear strategic intent ... to pursue its nuclear, biological, chemical and ballistic missile programmes', continuing efforts by the regime to 'sustain and where possible develop its indigenous capabilities', and 'the apparent considerable development, drawing on these capabilities, of Iraq's 'break-out' potential'.

And this, pretty much, is what we voters were told. It turned out to be wrong, but not, as so many have lazily called it, false. Now, you may take the view that the wrongness is sufficient reason to punish the government. That someone's head should roll for the fact that what was promised was different from what was delivered. But that, my fellow liberals, still wouldn't make the PM a liar. The charge is unfounded and in the run-up to a general election, whose result may not be the foregone conclusion that people expect, that could be important to know.